/*=====================================================================*
 *                   Copyright (C) 2011 Paul Mineiro                   *
 * All rights reserved.                                                *
 *                                                                     *
 * Redistribution and use in source and binary forms, with             *
 * or without modification, are permitted provided that the            *
 * following conditions are met:                                       *
 *                                                                     *
 *     * Redistributions of source code must retain the                *
 *     above copyright notice, this list of conditions and             *
 *     the following disclaimer.                                       *
 *                                                                     *
 *     * Redistributions in binary form must reproduce the             *
 *     above copyright notice, this list of conditions and             *
 *     the following disclaimer in the documentation and/or            *
 *     other materials provided with the distribution.                 *
 *                                                                     *
 *     * Neither the name of Paul Mineiro nor the names                *
 *     of other contributors may be used to endorse or promote         *
 *     products derived from this software without specific            *
 *     prior written permission.                                       *
 *                                                                     *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND              *
 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,         *
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES               *
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE             *
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER               *
 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,                 *
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES            *
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE           *
 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR                *
 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF          *
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT           *
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY              *
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE             *
 * POSSIBILITY OF SUCH DAMAGE.                                         *
 *                                                                     *
 * Contact: Paul Mineiro <paul@mineiro.com>                            *
 *=====================================================================*/

#include "mstep.h"
#include "qfunc.h"
#include "secant.h"

#include <assert.h>
#include <stdlib.h>
#include <string.h>

typedef struct _QfuncParams QfuncParams;
struct _QfuncParams 
{
  float                            kappa;
  unsigned int                     n_labels;
  const float*                     tau;
  const float*                     loglambda;
  const float*                     pz;
  const Rating*                    ratings;
  unsigned int                     n_ratings;
  const ParameterizedDistribution* priorlogalpha;
  float                            hq;
};

static float
qfunc_f (float  logalpha,
         float* dlogalpha,
         void*  params)
{
  QfuncParams* qfunc_params = (QfuncParams *) params;

  return qfunc (qfunc_params->kappa,
                logalpha,
                dlogalpha,
                qfunc_params->n_labels,
                qfunc_params->tau,
                qfunc_params->loglambda,
                qfunc_params->pz,
                qfunc_params->ratings,
                qfunc_params->n_ratings,
                qfunc_params->priorlogalpha,
                qfunc_params->hq);
}

float
mstep (float                            kappa,
       float*                           logalpha,
       unsigned int                     n_labels,
       const float*                     tau,
       const float*                     loglambda,
       const float*                     pz,
       const Rating*                    ratings,
       unsigned int                     n_ratings,
       const ParameterizedDistribution* priorlogalpha,
       float                            hq,
       unsigned int                     maxiter,
       float                            tol)
{
  QfuncParams qfunc_params = { .kappa = kappa,
                               .n_labels = n_labels,
                               .tau = tau,
                               .loglambda = loglambda,
                               .pz = pz,
                               .ratings = ratings,
                               .n_ratings = n_ratings,
                               .priorlogalpha = priorlogalpha,
                               .hq = hq };

  return secant (qfunc_f, &qfunc_params, logalpha, tol, maxiter);
}
